The present invention relates to a solid state image sensor, and more particularly to a charge-transfer type area image sensor.
Recently, instead of prior art optical cameras, development or research in regard to electronic cameras has become active. The term electronic cameras is used to refer to devices similar to, for example, a TV (Television) camera. Namely, electronic cameras comprise a solid state image sensor arranged on a portion corresponding to a film surface of an optical camera, to convert an optical signal into an electric signal with the solid state image sensor and a magnetic memory medium to store or write the electric signal, wherein the electronic cameras are not provided with a shutter mechanism in their optical system. The information thus stored can be changed into a hard copy, e.g. photograph obtainable with, such as, prior art optical cameras. Alternatively, the information thus stored can be changed into a soft copy, e.g. indication on a CRT (Cathode Ray Tube) display unit.
Reference is made to the detail of the electronic camera organization in which the technological starting point lies in the TV camera as stated above. In this instance, in lieu of using a shutter required for an optical camera, a photosensitive area and a storage area are provided in the image sensor. Thus, image information of an entire picture area sensed at the photosensitive area is transferred to the storage area within an extremely short time period. Then, the concerned signal is output from the storage area by means of signal readout means. As a result, the prior art image sensors require a photosensitive area and a storage area, resulting in a large size thereof.